The Duplicitous Duo
by LMXB
Summary: When the three most powerful women of National City end up at the same event, two of them conspire to have a little fun at the expense of the third.
1. Chapter 1

**Disclaimer:** I do not own Supergirl or the characters.

 **A/N:** This is set sometime after the events of the 'Girl of Steel'

* * *

"Hey Lena." Kara said walking into Lena's office. "Ms Grant? What are you doing here?"

"Well I heard there was a special event involving a Luther, a Super and children. It seemed a too interesting opportunity to miss. I mean you know what I always say about children?"

"They are more potent than biological weapons and like weapons of mass destruction should be locked away." Kara recalled earning a chuckle from Lena as Cat glared at her.

"I was worried you weren't going to make it." Lena said to Kara. "I'd hate you to miss Supergirl again."

"Yeah, about that. I need to head downstairs and meet a source."

"But she'll be here any moment." Lena said.

"I know. But I'll be back and failing that I'll see her when she sees the children you brought over." Kara smiled.

"Who is this source? Someone interesting?" Cat asked.

"Are you allowed to ask that?" Kara questioned.

"Probably not. Who are they?" Cat pressed.

"I can't tell you." Kara said, partly as she didn't have one.

"Now I am really intrigued. If not the source, what's the story?"

"The story?"

"Yes the story. I mean that's why you meet sources. Unless this is a drug deal in which case the person in question would be your dealer not your source….unless I have fallen out of touch with street slang."

"They're a source." Kara said. "But it is, um, too, um, too early, yes too early to talk about the source or the story."

"Even to me?" Lena asked.

"Um well, it's bad luck to discuss a story before meeting the source." Kara said.

"I didn't know that. I really do have a lot to learn." Lena said. "But you will be back won't you. For once it would be nice to talk to both of you at once."

"I will do everything I can. I mean sure, but I may be in the background. I mean tonight is about Supergirl right? The rest of us, apart from the children, should be practically invisible, so that's what I'll be. Anyway I should go."

As Kara finished fumbling her way through an excuse and left Lena glanced at Cat and saw the final moments of an eye roll.

"You know?" Lena asked before commenting. "Of course you know. You're Cat Grant."

"Know what?" Cat asked.

"The thing that apparently neither of us are meant to know."

"Which is?" Cat asked.

"That we both owe Kara our lives."

"I guess there is no point denying it. We are both intelligent women. And we would need to be blind to miss it. But why doesn't Kara know you know?" Cat asked.

"It is kind of adorable watching her try to come up with excuses." Lena said. "And I know it sounds stupid as they are the same, but I find it so much easier talking to Kara rather than Supergirl. I worry if Kara knew I knew, our relationship would change and I don't want to risk that. What's your excuse?"

"Kara has gone out of her way to prove she is not Supergirl. It seems silly to make her think all that effort was for nothing."

"So it has nothing to do with you wanting to drop your knowledge at a time that suits you?" Lena asked.

"The infamous Luthor paranoia?" Cat asked.

"Maybe, but that wasn't a denial from you." Lena smiled.

"While I admit I am sure I will enjoy watching Kara squirm when I tell her I know, there is no ulterior motive."

"How many people do you think know?" Lena asked.

"As in officially or unofficially?" Cat asked.

"Either."

"No idea. Based on the inept lying I have come across I would assume Winn and James as well as her family." Cat explained before asking. "Do you want to flex your Luthor muscles?"

"I'm sorry?"

"We both know your family taught you how to play with your kill before the kill, I am suggesting putting those skills to a fun and non psychotic use." Cat explained. "Trust me it is therapeutic."

"I'm intrigued."

"Just follow my lead." Cat said.

"Ms Grant, Ms Luthor." Supergirl greeted formally as she landed on the balcony.

"Supergirl, how good of you to join us." Cat smiled. "You don't seem surprised to see me."

"Um," Supergirl hesitated for a moment before saying. "My friends keep me informed."

"With sources like that perhaps you should be the journalist, not Kara." Cat mused.

"Talking of Kara, I'll go and get her." Lena said.

"Kara?" Supergirl asked.

"Yes. She was so looking forward to seeing you." Lena smiled.

"Don't disturb her, I'm sure she is busy." Supergirl said.

"Nonsense, I mean she was really looking forward to seeing you. I'll be right back." Lena said walking out of the door.

"Actually, I have to go. There's a fire downtown." Supergirl said trying to come up with an excuse for leaving.

"You will be back won't you?" Cat asked.

"Yes, I'll be back. As soon as the fire is out." Supergirl said taking to the sky.

-00-

"Kara! There you are. I've been looking for." Lena greeted when she saw a flustered Kara in the corridor.

"You have? Is there a problem?" Kara asked.

"Of course not. Supergirl is in my office and I know how much you want to see her. Come on we can't keep her waiting."

"Right, yes, of course." Kara said following Lena back to her office.

"Where is she?" Lena asked sounding disappointed.

"There was a fire. She'll be back soon." Cat said.

"Excellent. I would have hated for you to miss her." Lena said to Kara.

"It would have been fine. I mean she must be really busy and have better things to do than talk to me."

"But you're her bff." Cat said.

"I am?" Kara asked sensing there was a trap somewhere.

"Well you must be. She gives you more interviews than she ever gave me. But I will concede when you write articles about her you have an uncanny ability to channel her. It almost feels like she wrote the article herself." Cat explained.

"And there was the time she rescued me because you asked." Lena added. "And as you said she is really busy. Too busy to respond to requests from just anyone."

"But we can ask her when she gets here." Cat said. "I mean she'll be back soon, she wouldn't want to disappoint all those sick children would she?"

"Absolutely not." Kara said. "But until she gets here I need to do a couple of um, um..."

"Interviews?" Lena suggested.

"Yes interviews." Kara said relieved to have an excuse.

"And who are you interviewing?" Cat asked.

"Um, the children." Kara said.

"All of them? That is impressive." Cat said dryly.

"No, not all. But a few."

"I know I am new to the media world, but you know what would be a perfect interview?" Lena asked. "A joint interview with one of the children and Supergirl."

"A...a...a joint interview?" Kara asked.

"A little sickly for my taste, but the public will lap it up." Cat agreed. "You are learning fast Lena."

"Thank you." Lena smiled.

"Don't let us keep you from the sick children." Cat said. "We'll bring Supergirl down when she arrives."

"Right." Kara said pulling her phone out as she left the office.

"Calling her shapeshifting Martian friend?" Lena guessed.

"That would be my guess."

"Which one will he come as?"

"I would guess Kara. She can't risk his wooden performance as Supergirl in front of so many people."

"Ms Grant, Ms Luthor." Supergirl said walking into the office.

"I take it all the fires have been put out?" Cat asked.

"Yes."

"And you managed to get rid of the smokey smell. I am impressed. How did you do it?"

"My Kryptonian genes." Supergirl said, trying to sound confident.

"The children will be pleased, especially those with asthma." Cat said.

"Shall we go?" Lena suggested. "There are so many children who want to meet you."

"Of course." Supergirl said, praying that J'onn had turned up.

As they entered the large conference room where the children were assembled Lena asked.

"I wonder what happened to Kara. She said she was coming down to interview children. I hope she is okay."

"I'm sure she is fine." Supergirl said.

"Once again you are so well informed." Cat said. "Don't let us keep you. Your audience awaits." She said waving to the excited children.

As Supergirl went off to see the children 'Kara' entered the room.

"Kara? There you are." Lena grinned.

"Lena, Ms Grant." 'Kara' said whilst standing to attention.

"Did you have a muffin accident?" Cat asked.

"Excuse me?" A confused 'Kara' questioned.

"Well you've changed clothes." Cat pointed out as 'Kara' stood stiffly.

"I thought these were more appropriate for children." 'Kara' said as J'onn silently cursed his error. "Anyway I should initiate the interview." 'Kara' said before walking towards Supergirl and the children.

As 'Kara' blundered her way through the interview Lena was sure she could see Supergirl wince before finally taking control of the interview. As Supergirl effectively asked and answered the questions 'Kara' stood rigidly.

Once the interview was done Lena approached Kara and asked.

"Are you feeling okay? You don't quite seem yourself."

"I am fine." 'Kara' said, still standing like she was part of a military parade.

"Are you sure? I know you've had a hard day."

"I'm fine." 'Kara' repeated before forcing a smile.

"That's good. I would hate to think this took it's toll on you. Once again you have come to my rescue." Lena smiled before hugging 'Kara'. As the hug took place even Cat had a hard time keeping a straight face as 'Kara' glared at Supergirl.

"You are welcome." 'Kara' said as she awkwardly patted Lena's back before pulling out of the hug. "But I have to go. Alex needs me."

"Of course." Lena smiled as 'Kara' marched away.

-00-

"That was …. fun. Cruel, but fun." Lena said when it was just her and Cat that remained.

"It was." Cat agreed. "I do miss tormenting her. But Lena, despite what we did tonight I am very attached to Kara. Don't hurt her."

"She is my best friend, my only friend. I have no intention of hurting her….but I may toy with her. I mean I am a Luthor."

 **-The End**

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 **A/N:** Thanks for reading and reviewing.


	2. Chapter 2

"Being a reporter is not permission to be late." Cat chastised as Kara rushed into Lena's office.

"Sorry Ms Grant I got stuck in traffic...wait Ms Grant? What are you doing here?"

"Do I need you permission?" Cat asked.

"No umm, I meant I was um-"

"Words Kara, use them." Cat said.

"I thought you were in D.C." Kara finally said.

"And I thought you were an up and coming reporter. But seeing you aren't even aware that the President is visiting here it turns out we were both wrong."

"The President?" Kara asked looking round the room.

"I didn't mean now or here. She's coming tomorrow to National City." Cat said. "What on Earth do you do all day to not know this?"

"I um -"

"Words would be a start." Cat said shaking her head. "Seeing your association to me I don't want you to embarrass yourself and therefore me tomorrow at the press conference."

"What press conference?" Kara asked.

"Have you suffered some type of traumatic head injury?" Cat asked.

"No?" Kara replied.

"Was that a question or a denial?"

"A denial?"

"You don't sound sure." Cat said before turning to Lena who was silently watching the exchange. "Are you sure you want to risk using her tomorrow?"

"Using me? To do what?" Kara asked.

"Don't worry." Lena said. "It's just a simple demonstration."

"Demonstration of what?"

"My new species detector. It is like my alien detector only it actually gives species and traits. Including human so it isn't discriminatory. The President will announce buying several units for the White House and Cat thought a live demonstration would be a good idea. So I suggested you and Supergirl."

"Supergirl?" Kara asked.

"Yes. Supergirl. She will use it first to demonstrate as an alien and then you as a human."

"Supergirl has agreed?" Kara asked.

"Yes."

"She has?" Kara asked completely confused.

"I own Supergirl." Cat shrugged.

"But she is pretty busy...I mean what if there is an attack?" Kara asked.

"Then she swoops in the hero." Cat said.

-00-

"You okay?" Alex asked noticing how stressed Kara was looking.

"No."

"What's wrong?"

"Cat's back."

"For good?"

"No. Just for a press conference tomorrow."

"What's the issue?"

"Firstly it gave me major flashbacks to my first week working for her. Secondly she wants me to participate in the press conference."

"You?"

"Yes. And by me I mean both of the mes."

"That could be good. J'onn can pretend to be Supergirl while you be you. Having you both on live TV at the same time will help your cover."

"That's clever...but only solves half the problem."

"What's the other problem?"

"Lena's new species identification gadget is what is being launched at the press conference. If J'onn is me he'll still show as Martian and when I'm me I'll show as Kryptonian."

"Call in sick."

"To Ms Grant?"

"You don't work for her any more." Alex reminded her.

"So? You can never escape her power." Kara pointed out before exclaiming. "Oh, I have it."

"What?"

"I'll get the President to use it."

"That will show she's an alien." Alex said.

"Precisely. No one will believe that so the demo will be called off."

"Or people will believe it and it will destabilise the country." Alex said. "Turn up as Supergirl and call in sick as Kara."

"Ma'am, an alarm has been activated at L-Corp." Vasquez called to them.

"On it." Supergirl said flying off.

-00-

"Ms Luthor? Is everything okay?" Supergirl asked flying through her window.

"My fault, I needed to speak to you and seeing you haven't given me your phone number, despite all we have been through, I had to trigger an alarm." Cat said.

"What do you want?" Supergirl asked folding her arms across her chest.

"Please, no more games. I know you know why I summoned you."

"I-"

"Don't deny it. After all you are not surprised to see me, which means someone told you I was here and therefore why I was here." Cat said.

"I..." Supergirl started only to trail off confused.

"I thought it was prudent to have a run through tonight." Lena explained.

"Tonight?" Supergirl asked.

"Yes. Just as soon as Kara gets here." Lena said enthusiastically.

"Kara?"

"Someone you are clearly spending too much time with as your ability to use the English language is as bad as hers." Cat said.

"I need to go. There's a bank robbery." Supergirl said leaving.

-00-

"Help!" Supergirl said landing in front of Alex and J'onn. "They are doing a test run tonight."

"You're Supergirl. Tell Ms Grant you are not at her beck and call." J'onn said.

"Great plan. I tell you what, I'll be Kara and you be Supergirl and I'll watch as you tell her." Kara said.

"Fine, we won't do that." J'onn said.

"This is bad." Kara said gripping the back of a chair and accidentally crushing it. "That's it." Kara said before looking at J'onn. "I need you to be me. Kara me. And go to L-Corp. Now." Before J'onn could answer she had flown out of the DEO.

"When did I become your sister's body double?" J'onn asked.

"Well you do like the skirt." Alex pointed out.

-00-

"All arrested?" Cat asked when Supergirl returned.

"Arrested?"

"The bank robbers." Cat clarified.

"Yes."

"Really there was nothing on the news." Cat pointed out.

"By yes I meant..."

"No?" Lena suggested.

"Yes. They were arrested as in their progress was arrested, it came to a halt." Supergirl explained.

"I don't need an English lesson." Cat pointed out.

"The robbery was arrested by an alarm. They were gone by the time I got there." Supergirl said as the office door opened and Kara walked in.

"Ms Grant. Ms Lu- I mean, Lena." Kara greeted.

"You are helping with a demonstration, not attending boot camp. You are allowed to slouch." Cat pointed out when she saw Kara stand rigidly in the corner.

"Can we get this over with?" Supergirl asked.

"Of course." Lena said. "Just put your finger on here." Lena said holding out a box. In response Supergirl pressed her finger down hard enough to crush the device.

"I'm sorry. I don't know my own strength sometimes." Supergirl said.

"Not to worry, I have plenty more." Lena said. "I'll go get some spares."

"How many spares?" Kara asked.

"A whole warehouse." Lena smiled. "Although in this case a whole desk full." She said pulling one out of her top drawer.

"Shall we?" She said holding it up to Supergirl to gently touched the device.

"Look at that you are a Kryptonian." Cat said.

"You hear that?" Supergirl said before flying out of the window.

"Where are you going?" Cat asked Kara noticing she was leaving.

"There could be a story." Kara said disappearing in a hurry.

"When are you going to tell her the visit has been cancelled?" Lena asked Cat.

"Another hour? I'm curious what flimsy excuse she'll use next."

-00-

"I'm sorry did our professionalism interrupt your date?" Cat asked when Kara entered the office an hour later, shortly followed by Supergirl.

"It's busy out there." Supergirl replied.

"Quite. Well now everyone is here, perhaps we can finish the rehearsal. Kara, put your hand on the device." Cat instructed.

"You know what would make a great picture?" Kara asked. "The President using the device"

"You want me to use the President as a Beta tester?" Lena asked.

"I don't think that is a good idea." Supergirl said in a disparaging tone.

"The Secret Service were hesitant enough of me being in the same room as the President. Testing the device on her might give them heart failure." Lena pointed out.

"That is a good point." Supergirl said. "I need to go, there is an emergency down town." She said jumping from the window.

A moment later J'onn entered the office in a suit.

"Ms Luthor, I am Agent Henshaw. I believe you are supporting a press conference with the President tomorrow?"

"I am."

"And you are planning a demonstration?"

"I am."

"I need to take the device for testing. It will be waiting for you at the press conference."

"That's clever." Kara commented a little too loudly.

"What is clever?" Cat asked.

"Ensuring nothing is tampered with before the press conference." Kara said. "Keeping the President safe."

"You are praising Mulder for doing his job." Cat pointed out.

"And I thank him for his service." Kara said awkwardly as J'onn picked up the device and left the office.

"Ms Danvers you need to accompany me for vetting." J'onn said leading her out of the office.

"Once again that was a fun evening." Lena said. "I never thought I'd enjoy your visits."

"It's a new world." Cat commented. "Try not to break her before my next visit."

-The End

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A/N: Thanks for reading and reviewing


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